They call her synapse because she controls and reads the electrical impulses of all typical brain functions. It boils down to just your garden variety telepathy, but the way they explained it was more neurological/biochemical. She's been able to boost immune systems, paralyze people, turn powers off, and yes, control animals (people are animals). She has difficulty with things that don't have biochemical brains. She's not particularly fast or strong.

I guess this is one of those instances when Wikipedia was unreliable. Here's what Wikipedia said:

"Emily Guerrero

"Synapse (Emily Guerrero) is a superhero in Marvel Comics. The character, created by Gerry Duggan and Ryan Stegman, appeared in Uncanny Avengers Vol. 3 #1 (December 2015).

"Emily Guerrero lived with her younger brother and grandfather, Ivan, when the Terrigen Cloud affected their area. Emily emerged with telepathy, animal control, enhanced speed and super strength. Later, she joined the Avengers Unity Division under Captain America's leadership. Despite being new, Steve Rogers had faith in her even though she and teammate Rogue did not get along very well. She fought Super Adaptoid by getting a flock of pigeons to take it out."

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She doesn't really have a scifi costume. It looks more ninja than anything, but it's a fairly typical superhero costume.

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Golden Age? Jungle vixen? Huh?

Assuming she had control of animals and enhanced strength and speed, she sounded like Super-Tarzan.

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She's one of the NuHuman characters (humans that just learned they had the Inhuman gene after the Terrigen bomb). The bomb caused her grandfather to turn into some giant plant monster, and she's not too happy with Inhuman things because of that. Otherwise, she's just a normal Hispanic American girl.